← Back to 14. Serial Communication and Programmable Communication Interface

📝 Modem IC 8251 in 8085A Microprocessor

📖 From An Introduction To Microprocessor 8085 • 14. Serial Communication and Programmable Communication Interface • 9 questions available

Practice MCQs for Modem IC 8251 in 8085A Microprocessor. Test your knowledge with carefully crafted questions across easy, medium, and hard difficulty levels.

🔄 Last updated: 2026-07-30

2
Easy Questions
4
Medium Questions
3
Hard Questions

📝 Sample Questions

Q1. What is the maximum number of bytes that a single DMA operation can transfer using the 8257 controller?

🔹 A. 8 KB
🔹 B. 16 KB
🔹 C. 32 KB
🔹 D. 64 KB

💡 Difficulty: easy | ✅ Correct: B

Q2. In a system where a peripheral asserts a DMA request, which signal tells the microprocessor that it must release the bus so the DMA controller can take control?

🔹 A. HLDA
🔹 B. HRQ
🔹 C. DACK
🔹 D. READY

💡 Difficulty: medium | ✅ Correct: B

Q3. Two channels need to transfer 10 KB each, but the DMA controller can move only 16 KB in a single operation. Which technique allows both transfers to complete without exceeding the limit?

🔹 A. Increase the terminal count register
🔹 B. Use channel chaining
🔹 C. Enable burst mode
🔹 D. Split each transfer into two smaller blocks

💡 Difficulty: hard | ✅ Correct: A

⬆️ View all questions in the quiz below

🔗 Related Topics

📝 Serial Data Communication IC 8251 in 8085A Microprocessor📝 Serial Communication Standard IC 8251 in 8085A Microprocessor📝 Asynchronous Software Approach IC 8251 in 8085A Microprocessor📝 Programmable Communication Interface IC 8251 in 8085A Microprocessor📝 Block Diagram of 8251A in 8085A Microprocessor
🚀 Start Quiz 📝 Practice Mode